Canada, US: Adverse winter weather conditions forecast across south-central and southeastern Canada and north-central and northeastern US through Dec. 6 /update 3

Adverse winter weather conditions are forecast across parts of south-central and southeastern Canada and the north-central and northeastern US through at least Dec. 6. A winter storm system moving eastward across the region is expected to bring widespread snowfall and strong winds across the Great Lakes and into parts of the northeastern US and southeastern Canada over the coming days. Widespread snowfall accumulations of 5-30 cm (2-12 inches) are expected across parts of the region, with localized higher amounts possible. The combination of heavy snowfall and gusty winds may cause blizzard conditions in places. Hazardous driving conditions are likely across the affected areas due to icy roads and reduced visibility caused by blowing snow.

As of early Dec. 4, the US National Weather Service (NWS) has issued winter storm warnings for parts of far northern Minnesota, northern, southwestern, and western Michigan, central Pennsylvania, northeastern West Virginia, central and northern New York, southern Vermont, and northern Maine. Blizzard warnings have been issued for parts of far northwestern Maryland and eastern West Virginia and lake effect snow warnings for parts of northeastern Ohio, western New York, and northwestern Pennsylvania. Winter weather advisories are in place across much of the rest of the affected area in the US.

Environment Canada has issued red snow squall warnings (the highest level on a three-tier scale) for parts of south-central and southeastern Ontario and red snowfall warnings for parts of central and northern New Brunswick and southeastern Quebec. Red strong wind warnings have been issued for parts of eastern Nova Scotia and Iles-de-la-Madeleien in Quebec and a yellow snow squall watch is in place for eastern Prince Edward Island. Grey weather advisories and grey special weather statements for heavy snowfall, blowing snow, and strong winds are in place across much of the rest of the affected area in Canada.

Officials will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Snow accumulations are likely across the affected area. Lesser snowfall totals are possible where sleet and freezing rain mix with snow. In addition to the heavy snow, strong wind gusts could lead to periods of blowing and drifting snow. Sporadic power outages may occur throughout the affected area.

The inclement weather will likely cause widespread ground and air transport disruptions across the affected areas. Traffic and commercial trucking delays are probable along regional highways. Dangerous and challenging driving conditions are also likely on secondary and rural roads as maintenance crews prioritize clearing major routes. Authorities will likely close stretches of highways if driving conditions become too hazardous. Gusty winds will threaten to topple high-profile vehicles throughout the affected areas. Mountain passes and tunnels will probably be closed as a precautionary measure during periods of intense snowfall. The disruptive weather will likely cause delays and cancellations at airports in the affected regions. Heavy, wet snow and strong winds could bring down power lines and trees with foliage.